Hi! I'm one of the last Fraundorfers in Salzburg. The Fraundorfers mostly came from Upper-Austria and south-eastern part of Bavaria. Some years ago there was only a very numer of Fraundorfers in Austria at all. Besides, if you spell it Fraundorfer or Frauendorfer: in most cases the registration in offical or clerical books was made by clerks or preachers or ... But how they spelled your name this was most of the time just up to them (especially in times when most people couldn't read or write). Just to tell you: I've got a half-sister, and after birth some official spelled her name "Frauendorfer", and as this was realized quite late, and as the change of the name cost a fortune (afterwards), well, she and her daughters are all called "Frauendorfer".
Regards Stefan